Saturday, March 15, 2008

Modified cell for our Cheapy-ERF

The former one is good in design but poor in execution due to a poor record of the correct measurement. Now, I found that it's better to have a more secure cell than the last design which uses only two very short stopper to hold the heavy filter in place.

Without a rolling machine, I have been thinking of ways to make a cylindrical cell. Finally, I found that with the last ring style mounting, I could actually use slightly longer screw plus some paper (just as light shield) to form a cell.

Of course, this is not a very good fit, and I will be adding some safety string to lock the filter in place while using. However, I found that even without any safety string, the filter will not be dropped even when the scope is pointing horizontally to the ground, and that's more than enough for actual usage as a scope will not be pointing anything lower than horizontal level.

I consider this the final solution for the mounting of this Cheapy-ERF.


Ken "Merlin66" Harrison said...

I've just mounted my combo ERF into a 4" PVC end, clear aperture 100mm and successfully used some hot glue ( easily available, sticks very well and can be removed without damage to optics!)
Using small cork spacers I can tilt the ERF on the end of the scope.

Oldfield said...


Thank you for your idea, neat!

BTW, do you find tilting the ERF helps to reduce the internal reflection?